陶瓷球填料生物滴滤塔降解甲苯废气

The Purification experiments of waste gas containing low concentration toluene were made in trickling biofilter with ceramic spheres. The effects of liquid flow rate,gas flow rate,pH of circulation liquid, and toluene concentration in inlet gas on the purification efficiency of trickling biofilter were investigated. The pressure drop of the trickling biofilter was also measured during experiments.Increasing liquid flow rate and gas flow rate resulted in the decrease of purification efficiency of trickling biofilter. The highest purification efficiency of trickling biofilter was found at the circulation liquid pH of 7. The porosity of the packing material at the inlet of gas was higher than that at the outlet of gas in biofilter after continuous operation in 50 days. The decrease in the porosity of packing material caused a great increase in the pressure drop of the biofilter.     

Mass transfer performance of structured packings in a CO2 absorption tower

This paper studies the mass transfer performance of structured packings in the absorption of CO2 from air with aqueous NaOH solution. The Eight structured packings tested are sheet metal ones with corrugations of different geometry parameters. Effective mass transfer area and overall gas phase mass transfer coefficient have been measured in an absorption column of 200 mm diameter under the conditions of gas F-factor in 0.38–1.52 Pa0.5 and aqueous NaOH solution concentration of 0.10–0.15 kmol·m?3. The effects of gas/liquid phase flow rates and packing geometry parameters are also investigated. The results show that the effective mass transfer area changes not only with packing geometry parameters and liquid load, but also with gas F-factor. A new effective mass transfer area correlation on the gas F-factor and the liquid load was proposed, which is found to fit experiment data very well.     

Influence of slug flow on flow fields in a gas–liquid cylindrical cyclone separator:A simulation study

A simulation method for slug flow based on the VOF multiphase flow model was implemented in ANSYS? Fluent via a user-defined function(UDF) and applied to the dissipation of liquid slugs in the inlet pipe of a gas–liquid cylindrical cyclone(GLCC) separator while varying the expanding diameter ratio and angle of inclination. The dissipation of liquid slug in inlet pipe is analyzed under different expanding diameter ratios and inclination angles.In the inlet pipe, it is found that increasing expanding diameter ratio and inclination angle can reduce the liquid slug stability and enhancing the effect of gravity, which is beneficial to slug flow dissipation. In the cylinder, increasing the expanding diameter ratio can significantly reduce the liquid carrying depth of the gas phase but result in a slightly increase of the gas content in the liquid phase space. Moreover, increasing the inclination angle results in a decrease in the carrying depth of liquid in the vapor phase, but enhances gas–liquid mixing and increases the gas-carrying depth in the liquid phase. Taking into consideration the dual effects of slug dissipation in the inlet pipe and carrying capacity of gas/liquid spaces in the cylinder, the optimal expanding diameter ratio and inclination angle values can be determined.     

鼓泡塔中低浓度表面活性剂对CO2吸收传质系数的影响（英文）

The effect of different surfactants (n-octyltrimethylammonium bromide (OTABr), sodium dodecyl benzene sulfonate (SDBS) and Tween 80) with different critical micelle concentrations (CMC) on the CO2 absorption into aqueous solutions in a bubble column is analyzed in the present work. The presence of these surfactants in-creased the gas–liquid interfacial area, and decreased the liquid phase mass transfer coefficient, but with signif-icant different extent. The results indicated that the CMC can be a key parameter affecting the mass transfer of CO2 absorption into a dilute aqueous solution of a surfactant. Sardeing's model was used to fit the experimental data successfully by re-correlating the parameters.     

Modeling the rate of corrosion of carbon steel using activated diethanolamine solutions for CO_2 absorption

A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO_2). Piperazine(PZ) is used as the activator in diethanolamine(DEA) aqueous solutions. The developed model for corrosion takes into consideration the effect of fluid flow,transfer of charge and diffusion of oxidizing agents and operating parameters like temperature, activator concentration, CO_2 loading and pH. The study consists of two major models: Vapor–liquid Equilibrium(VLE) model and electrochemical corrosion model. The electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk solution. The results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of metal. An increase in concentration of activator, increases the rate of corrosion of carbon steel in mixtures of activated DEA.     

超重力旋转填料床中柠檬酸钠缓冲液吸收二氧化硫(英文)

Absorption of SO2 from a SO2/air mixture with sodium citrate buffer solution was investigated using a rotating packed bed(RPB) in laboratory scale.The effects of operating parameters,such as the rotation speed of RPB,liquid-gas ratio,inlet gas flow rate,inlet concentration of SO2 in flue gas,sodium citrate buffer concentration and initial pH of absorption solution,on the SO2 concentration in the absorption solution or removal efficiency of SO2 were examined.Incremental rate of sulfate radical ions in the absorption solution was also examined.Experimental results indicate that the efficiency of this regenerative process will be improved by using RPB under appropriate operating conditions,and the generation of SO2-4 will be restrained in the process in RPB.     

Absorption of Low Concentration Sulfur Dioxide Using Liquid-containing Microporous Membrane

The absorption of low concentration SO2 in flue gas by using the module of liquid-containing microporous membrane which is made up of hollow fiber and citric acid-sodium citrate buffer solution was investigated. The absorption efficiency of hydrophilic and hydrophobic membranes by using the concept of dynamic contact angle was mainly studied. The influences on absorption efficiency from absorption time, flowrate of gas phase, SO2 concentration of gas phase, air pressure, citrate concentration, pH value of solution as well as the generation of sulfate radical in absorption solution were examined. The results indicate that the hydrophobic hollow fiber membrane is better than hydrophilic membrane, the absorption efficiency decreases with increasing absorption time, gas phase flowrate, gas phase SO2 concentration and air pressure, the absorption rate and capacity of SO2 can be improved by increasing the citrate concentration, the absorption efficiency can be improved by increasing the pH value of citrate solution, the concentration of SO42- in absorption solution increases linearly with the absorption time at a rate around 0.192 g/(L×h).     

活性炭粒子对K2CO3溶液中CO2化学吸收的强化

The enhancement of chemical absorption of CO2 by K2CO3/H2O absorbents in the presence of activated carbon （AC） particles was investigated. The results show that the gas absorption rates can be enhanced significantly in the presence of AC particles, and the maximum enhancement factor 3.7 was observed at low stirring intensities. The enhancement factor increased rapidly with the solid loading during the initial period of absorption and then be- came mild gradually to a maximum value. Both the liquid-solid contact area and the probability of solid particles residing at the gas-liquid interface decreased with the increase of the particle size, leading to a negative effect on the enhancement of mass transfer. The influence of the particles on gas absorption decreased with the reaction rate. The stirring speed changed the interfacial coverage and mass transfer rate on the liquid side and consequently affected the mass transfer between the gas and liquid phases; the enhancement factor decreased with the stirring intensity. A heterogeneous two-zone model was proposed for predicting the enhancement factor and the calculated results agreed well with the experimental data.     

MDEA与哌嗪、二乙醇胺混合溶液吸收二氧化碳速率研究

Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA.     

Absorption Rate of CO_2 into MDEA Aqueous Solution Blended with Piperazine and Diethanolanline

Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with di-ethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA+PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA+PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA.     

Comparison of Overall Gas‐Phase Mass Transfer Coefficient for CO2 Absorption between Tertiary Amines in a Randomly Packed Column

The mass transfer performance of CO₂ absorption into an innovative tertiary amine solvent, 1‐dimethylamino‐2‐propanol (1DMA2P), was investigated and compared with that of methyldiethanolamine (MDEA) in a packed column with random Dixon‐ring packing. All experiments were conducted under atmospheric pressure. The effects of inert gas flow rate, amine concentration, liquid flow rate, CO₂ loading, and liquid temperature on mass transfer performance were analyzed and the results presented in terms of the volumetric overall mass transfer coefficient (K_Ga_v). The experimental findings clearly indicate that 1DMA2P provided better mass transfer performance than MDEA. For both 1DMA2P and MDEA solutions, the K_Ga_v increased with rising amine concentration and liquid flow rate, but decreased with higher CO₂ loading. The inert gas flow rate only slightly affected the K_Ga_v. A satisfactory correlation of K_Ga_v was developed for the 1DMA2P‐CO₂ system.     

Mass transfer performance and correlations for CO2 absorption into aqueous blended of DEEA/MEA in a random packed column

The mass transfer performance of CO₂ absorption into blended N,N‐diethylethanolamine (DEEA)/ethanolamine (MEA) solutions was investigated using a lab‐scale absorber (H = 1.28 m, D = 28 mm) packed with Dixon ring random packing. The mass transfer coefficient K_Ga_v, the unit volume absorption rate Φ, outlet concentration of CO₂ (y_CO2), and the bottom temperature T_bot of CO₂ in aqueous DEEA/MEA solutions were determined over the feed temperature range of 298.15–323.15 K, lean CO₂ loading of 0.15–0.31 mol/mol, over a wide range of liquid flow rate of 3.90–9.75 m³/m²‐h, by using inert gas flow rate of 26.11–39.17 kmol/m²‐h and 6–18 kPa CO₂ partial pressure. The results show that liquid feed temperature, lean CO₂ loading, liquid flow rate, and CO₂ partial pressure had significant effect on those parameters. However, the inert gas flow rate had little effect. To allow the mass transfer data to be really utilized, K_Ga_v and y_out correlations for the prediction of mass transfer performance were proposed and discussed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3048–3057, 2017     

Mass transfer investigation and operational sensitivity analysis of amine-based industrial CO2 capture plant

In this article, the industrial process of CO₂ capture using monoethanolamine as an aqueous solvent was probed carefully from the mass transfer viewpoint. The simulation of this process was done using Rate-Base model, based on two-film theory. The results were validated against real plant data. Compared to the operational unit, the error of calculating absorption percentage and CO₂ loading was estimated around 2%. The liquid temperature profiles calculated by the model agree well with the real temperature along the absorption tower, emphasizing the accuracy of this model. Operational sensitivity analysis of absorption tower was also done with the aim of determining sensitive parameters for the optimized design of absorption tower and optimized operational conditions. Hence, the sensitivity analysis was done for the flow rate of gas, the flow rate of solvent, flue gas temperature, inlet solvent temperature, CO₂ concentration in the flue gas, loading of inlet solvent, and MEA concentration in the solvent. CO₂ absorption percentage, the profile of loading, liquid temperature profile and finally profile of CO₂ mole fraction in gas phase along the absorption tower were studied. To elaborate mass transfer phenomena, enhancement factor, interfacial area, molar flux and liquid hold up were probed. The results show that regarding the CO₂ absorption, the most important parameter was the gas flow rate. Comparing liquid temperature profiles showed that the most important parameter affecting the temperature of the rich solvent was MEA concentration.     

Absorption of carbon dioxide by the absorbent composed of piperazine and 2-amino-2-methyl-1-propanol in PVDF membrane contactor

This paper tests the performance of microporous polyvinylidinefluoride (PVDF) hollow fiber in a gas absorption membrane process (GAM) using the aqueous solutions of piperazine (PZ) and 2-amino-2-methyl-1-propanol (AMP). Experiments were conducted at various gas flow rates, liquid flow rates and absorbent concentrations. Experimental results showed that wetting ratio was about 0.036% when used with the aqueous alkanolamine solutions, while that was 0.39% with aqueous piperazine solutions. The CO₂ absorption rates increased with increasing both liquid and gas flow rates at N_Re < 20. The increase of the PZ concentration showed an increase of absorption rate of CO₂. The CO₂ absorption rate was much enhanced by the addition of PZ promoter. The resistance of membrane was predominated as using a low reactivity absorbent and can be neglected as using absorbent of AMP aqueous solution. The resistance of gas-film diffusion was dominated as using the mixed absorbents of AMP and PZ. An increase of PZ concentration, the resistance of liquid-film diffusion decreased but resistance of gas-film increased. Overall, GAM systems were shown to be an effective technology for absorbing CO₂ from simulated flue gas streams, but the viscosity and solvent-membrane relationship were critical factors that can significantly affect system performance.     

Parametric studies of carbon dioxide absorption into highly concentrated monoethanolamine solutions

Carbon dioxide (CO₂) absorption into highly concentrated solutions of monoethanolamine (MEA) was studied. The effect of operating parameters on the overall mass transfer coefficient (K_Ga_v) was determined in a pilot‐plant scale absorption unit. The (K_Ga_v) increased at low solution concentrations, decreased at intermediate concentrations, and increased as the concentration became high (54 wt%). The (K_Ga_v) increased with an increasing liquid flow rate, decreased with an increase in either the CO₂ loading or the CO₂ partial pressure, and was not affected by the inert gas flow rate. Finally, structured 4A Gempak packing produced (K_Ga_v) values twice as high as randomly packed IMTP#15 or 16‐mm Pall Ring systems.     

Numerical investigation on CO2 absorbed in aqueous N‐methyldiethanolamine + piperazine

A multiphase and multicomponent mass transfer model of CO₂ absorbed in aqueous N‐methyldiethanolamine and piperazine (PZ) was built in the study. In the model, a simple method of mass transfer between phases was proposed. Besides, the hydrodynamics, thermodynamics, and complex reversible chemical reaction were considered simultaneously. The model was validated by comparing with the previous experimental data which showed that simulated results can represent the experimental data with reasonable accuracy. Based on the model, the effects of gas velocity, liquid load and CO₂ loading on the absorption rate, and enhancement factor were analyzed. Model results showed that the enhancement factor increased with a rising gas velocity while decreased with a rising liquid load or CO₂ loading. The change of enhancement factor with CO₂ loading was similar to that of equilibrium concentration of PZ which indicated that PZ was significant to the absorption process. Furthermore, the distributions of specie concentrations were discussed in detail. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2386–2393, 2017     

Removal of ozone from air by absorption in a rotating packed bed

This work investigated the feasibility of ozone (O₃) absorption by H₂O₂ solution in a rotating packed bed (RPB). The overall volumetric gas-phase mass transfer coefficients (K_Ga) were determined as functions of pH of H₂O₂ solution, O₃ concentration, H₂O₂ concentration, RPB speed, gas flow rate, liquid flow rate, and RPB type. The K_Ga values were highly dependent on the pH of H₂O₂ solution. Also, the K_Ga values increased with O₃ concentration and H₂O₂ concentration. As expected, the RPB speed positively affected the K_Ga values for all RPBs. Furthermore, the obtained results indicated that the K_Ga values increased as the inner radius of the bed was increased and the outer radius of the bed was decreased. Moreover, the K_Ga values increased with an increasing liquid flow rate and an increasing gas flow rate for all RPBs. The dependences of K_Ga on the gas flow rate and the liquid flow rate indicated that the resistance to mass transfer in the gas-phase for O₃ absorption was higher than that in the liquid phase in the RPB.     

Simultaneous Absorption of Hydrogen Sulfide and Carbon Dioxide into di-isopropanolamine Solution

The simultaneous absorption of hydrogen sulfide and carbon dioxide into di-isopropanolamine (DIPA) solution was investigated in a 183 cm long, 2.72 cm OD wetted-wall column at atmospheric pressure. The influence of liquid flow rate, gas flow rate, temperature and liquid concentration on the absorption rate, overall gas-phase mass transfer coefficient and selectivity factor were studied at a constant gas feed ratio. The results show that the absorption rate of CO₂ increases rapidly with increasing liquid flow rate (the Reynolds number of the turbulent liquid film ranges from 2600 to 4350) but increases moderately with increasing gas flow rate (G = 18-91 L/min), indicating that it is liquid-phase mass transfer controlled. In contrast, the absorption rate of H₂S increases very slowly with increasing liquid flow rate but increases rapidly with increasing gas flow rate, indicating that it is gas-phase mass transfer controlled. The absorption rate of CO₂ also increases with increasing temperature (26-80°C) but H₂S absorption rate decreases with increasing temperature. When the concentration of DIPA solution increases from 0.2 to 2.6 mol/L, the absorption rate of both CO₂ and H₂S increases but with a larger rate of increase for CO₂ For selective H₂S removal, it is preferable to operate at low liquid and high gas flow rates, low temperatures and low DIPA concentrations.     

CO_2捕集的吸收溶解度计算和过程模拟

为了降低CO2吸收法捕集技术的能耗和成本,以目前常用的单乙醇胺(MEA)溶液吸收CO2为例,采用电解质非随机双流体热力学模型(E-NRTL),对溶液中的CO2气体溶解度进行计算,计算过程包含了化学反应平衡和汽液平衡,计算结果和文献数据相吻合。在此基础上,建立了CO2吸收过程模拟程序和包括解吸能耗、气体压缩能耗以及液体输送能耗的过程总体能耗的计算方法,继而通过过程模拟分析了吸收塔和解吸塔压力、溶液浓度和流量等因素对吸收捕集过程的总体能耗的影响,获取了最优的工艺条件,为以后新CO2吸收捕集过程提供能耗分析方法基础。     

Absorber intercooling in CO2 absorption by piperazine‐promoted potassium carbonate

Intercooling was evaluated as a process option in CO₂ absorption by piperazine (PZ) promoted potassium carbonate. The system performance with 4.5 m K⁺/4.5 m PZ was simulated by a model in Aspen Plus® RateSep?. The absorber was evaluated for use with a double matrix stripper by optimizing the position of the semilean feed and intercooling stages to maximize CO₂ removal. Additionally, a simple absorber system was modeled to observe the effect of intercooling on systems with variable CO₂ lean loading. Intercooling increases CO₂ removal by as much as 10% with the double matrix configuration. With a simple absorber, the effectiveness of intercooling depends on solvent rate. Near a critical liquid/gas ratio (L/G) there is a large improvement with intercooling. This is related to the position of the temperature bulge. An approximation is proposed to estimate the critical L/G where intercooling may maximize removal. © 2009 American Institute of Chemical Engineers AIChE J, 2010